473 research outputs found

    Spin-transfer mechanism of ferromagnetism in polymerized fullerenes: AbinitioAb initio calculations

    Full text link
    A mechanism of the high temperature ferromagnetism in polymerized fullerenes is suggested. It is assumed that some of the C60_{60} molecules in the crystal become magnetically active due to spin and charge transfer from the paramagnetic impurities (atoms or groups), such as hydrogen, fluorine, hydroxyl group OH, amino group NH2_2, or methyl group CH3_3, dispersed in the fullerene matrix. The exchange interaction between the spins localized on the magnetically active fullerenes is evaluated using \textit{ab initio} calculations. The nearest neighbour and next nearest neighbour exchange interaction is found to be in the range 0.1÷0.30.1\div 0.3 eV, that is, high enough to account for the room temperature ferromagnetism.Comment: typos corrected, 8 pages, 3 figures, LaTe

    The inflammation markers in serum of tumor-bearing rats after plasmonic photothermal therapy

    Get PDF
    We report on plasmonic photothermal therapy of rats with inoculated cholangiocarcinoma through the intratumoral injection of PEG-coated gold nanorods followed by CW laser light irradiation. The length and diameter of gold nanorods were 41±8 nm and 10±2 nm, respectively; the particle mass-volume concentration was 400 μg/mL, which corresponds to the optical density of 20 at the wavelength 808 nm. The tumor-bearing rats were randomly divided into three groups: (1) without any treatment (control); (2) with only laser irradiation of tumor; (3) with intratumoral administration of gold nanorods and laser irradiation of tumors. An hour before laser irradiation, the animals were injected intratumorally with gold nanorod solutions in the amount of 30% of the tumor volume. The infrared 808-nm laser with power density of 2.3 W/cm2 was used for plasmonic photothermal therapy (PTT). The withdraw of animals from the experiment was performed 24 h after laser exposure. The content of lipid peroxidation products and molecular markers of inflammation (TNF-α, IGF-1, VEGF-C) was determined by ELISA test in serum of rats. The standard histological techniques with hematoxylin and eosin staining were used for morphological examination of tumor tissues. It was revealed that the significant necrotic changes were noted in tumor tissue after plasmonic photothermal therapy, which were accompanied by formation of inflammatory reaction with release of proinflammatory cytokines and lipid peroxidation products into the bloodstream

    Assessment of Resistance in <i>Burkholderia pseudomallei</i> to Benzalkonium Chloride and Antibiotics

    Get PDF
    The aim of the study was to investigate the features of resistance formation in Burkholderia pseudomallei to quaternary ammonium compounds, as well as to analyze its influence on the development of antibiotic resistance.Materials and methods. 10 strains of melioidosis causative agent with typical cultural and morphological properties have been studied. The selection of variants resistant to benzalkonium chloride was carried out by successive passages on a dense nutrient medium with the addition of a disinfectant in increasing concentrations. The determination of sensitivity to benzalkonium chloride was performed through serial dilutions in agar, to antibacterial drugs from the groups of sulfonamides, β-lactams and tetracyclines – using disk diffusion method. Statistical processing of the obtained results was conducted with the help of the Microsoft Excel 2019 software. Arithmetic mean values and errors of mean values were calculated. The significance of differences between the parameters was determined applying Student’s t-test.Results and discussion. All parental strains showed a similar degree of resistance to the disinfectant compound and most of the strains – susceptibility to the antibiotics tested. Cultivation of B. pseudomallei strains on a nutrient medium with the addition of benzalkonium chloride led to an increase in resistance to this disinfectant. In addition, an increase in the level of resistance to all studied antibiotics was found. Statistical processing of the data collected revealed a significant correlation between the change in sensitivity to benzalkonium chloride and the emergence of resistance to amoxicillin/ clavulanic acid and ceftazidime. It was found that the causative agent of melioidosis, with a natural high susceptibility to benzalkonium chloride, has a high potential for developing resistance to this disinfectant compound, which is of practical importance in the development of disinfection regimens using quarternary ammonium compounds. For the first time, a direct correlation between a decrease in the sensitivity to benzalkonium chloride in B. pseudomallei and emergence of resistance to amoxicillin/clavulonic acid and ceftazidime has been demonstrated

    Аnalysis of the cytokine profile of blood serum and tumor supernatants in breast cancer

    Get PDF
    Background. A crucial role in the development of cancer is played by the tumor microenvironment (TM) – a microenvironment that is formed as a result of the interaction between the tumor tissue and macroorganism cells. The concentration of TM cytokines in the blood varies depending on the activity of the tumor and the presence of a metastatic process. It is advisable to study the existing mediator imbalance of TM, its characteristic features in the process of tumor development for the diagnosis and prognosis of the tumor process.The aim. To identify markers of tumor progression in the study of tissue and serum cytokines in women diagnosed with breast cancer.Materials and methods. The object of the study is blood serum cytokines and tumor supernatants (MCP-1, VEGF, TNF-α, IFN-γ, TGF-β1, G-CSF, GM-CSF). The study involved 80 patients with breast cancer aged 50–69 years and 26 practically healthy women aged 41 to 62 years. A standard examination of women was conducted; a cytokine profile study was conducted before the appointment of therapy. To study the cytokine profile at the tissue level, tumor biopsies (n = 30) and biopsies of unchanged breast tissue (n = 6) were incubated to determine the production of MCP-1, VEGF, TNF-α, IFN-γ, TGF-β1, G-CSF, GM-CSF.Results. There was a moderate positive correlation between the stage of the disease and the level of TGF-β1, MCP-1 blood serum, a weak one – with G-CSF. In the incubated tumor tissue, a high positive correlation of cytokines on the stage of the disease is observed in growth factors: VEGF (R = 0.79; p &gt; 0.05) and TGF-β1 (R = 0.61; p &gt; 0.05).Conclusion. The study revealed the characteristic features of the cytokine profile of blood serum and tumor tissue in breast cancer at local and widespread stages. The revealed differences in the level of cytokines should be used as additional diagnostic indicators of the degree of activity and prevalence of the tumor process

    Эндотелиальная дисфункция и процессы апоптоза в патогенезе когнитивных нарушений у больных с артериальной гипертензией

    Get PDF
    Eighty patients with arterial hypertension (AH), aged 52,4 years, were studied. A diagnosis of mild cognitive impairment (MCI) in 61 patients met traditional clinical approach, neuropsychological examination. Significant correlation between the level of cognitive dysfunction and blood concentration of NO, endothelin-1 and apoptosis markers in researching groups were found. The results obtained suggest that markers of endothelial dysfunction and apoptosis could prove to be the early predictors of cognitive impairment in patients with arterial hypertension.Обследовано 80 больных с артериальной гипертензией (АГ), средний возраст которых составил 52,4 года. С помощью традиционного клинического метода исследования, нейропсихологического тестирования у 61 пациента с АГ выявлены умеренные когнитивные расстройства. Установлена корреляционная зависимость между уровнем когнитивных нарушений и концентраций NO, эндотелина-1 и маркеров апоптоза в исследуемых группах лиц. Полученные результаты показывают, что данные показатели могут являться предикторами развития когнитивной дисфункции у больных с артериальной гипертензией

    Specific features of memory consolidation and reconsolidation in older individuals with vision and hearing impairments

    Get PDF
    This study aimed to specify this issue by analyzing memory consolidation and reconsolidation processes in older people with sensory deficit

    Nanoparticle delivery systems in the treatment of diabetes complications

    Get PDF
    Diabetes mellitus, an incurable metabolic disease, is characterized by changes in the homeostasis of blood sugar levels, being the subcutaneous injection of insulin the first line treatment. This administration route is however associated with limited patients compliance, due to the risk of pain, discomfort and local infection. Nanoparticles have been proposed as insulin carriers to make possible the administration of the peptide via friendlier pathways without the need of injection, i.e., via oral or nasal routes. Nanoparticles stand for particles in the nanometer range that can be obtained from different materials (e.g., polysaccharides, synthetic polymers, lipid) and are commonly used with the aim to improve the physicochemical stability of the loaded drug and thereby its bioavailability. This review discusses the use of different types of nanoparticles (e.g., polymeric and lipid nanoparticles, liposomes, dendrimers, niosomes, micelles, nanoemulsions and also drug nanosuspensions) for improved delivery of different oral hypoglycemic agents in comparison to conventional therapies.The authors acknowledge the financial support received from Portuguese Science and Technology Foundation (FCT/MCT) and from European Funds (PRODER/COMPETE) under the project reference M-ERA-NET/0004/2015-PAIRED, co-financed by FEDER, under the Partnership Agreement PT2020. The authors also acknowledge the support of the research project: “Nutraceutica come supporto nutrizionale nel paziente oncologico”, CUP: B83D18000140007.info:eu-repo/semantics/publishedVersio
    corecore